1) Bulk quantities of rabbit hemoglobin alpha- and Beta-mRNA and primate hemoglobin alpha-, Beta- and gamma-mRNA will be obtained by immunologic isolation of specific polysomes using specific antibodies to chains. Thereafter purity will be established by a combination of Dintzis-Naughton analysis of polysome nascent peptides and cell-free translational assay of mRNA. 2) Iodinated purified rabbit alpha- and Beta-mRNA and derivative P32, H3, or iodinated cDNA will be hybridized to rabbit DNA so as to measure relative numbers of alpha and Beta genes. Primate mRNA's and their derivatives will be hybridized with human DNA so as to measure relative numbers of alpha, Beta, and gamma genes in man. 3) Preliminary sequence characterization of iodinated alpha- and Beta-mRNA from rabbit will begin. 4) Attempts will be made to lessen non-specific trapping of polysomes in immunoprecipitates so that precipitates themselves rather than the soluble remainders of immunoprecipitation can be used for isolation of specific mouse polysomes. If successful, detailed undetected characterization of P32 alpha- and Beta-mouse mRNA derived from leukemic cells will begin. 5) Profile differences between polysomes for human newborns, adults, sicklemics and thalassemics will be sought using I125-anti-alpha, anti- Beta, and anti-gamma.